WHY DO IT?
I like to think of it
more as OPTIMIZING my G4 Processor. To some folks the
term overclocking has bad connotations. Optimizing your
Macintosh G4 Tower (QuickSilver Motherboard) is an
inexpensive get more speed. It does require a high level
of skill, good desoldering skills, steady hands and good
vision and or magnifying equipment. Almost all G4
QuickSilvers will overclock at least one level. In other
words, your 733 will probably run 800 or your 800 may run
867. Most G4 processors were very capable. Your machine
should be in good working order. Overclocking will make
any existing problems worse. Good well tested and well
seated ram, a fresh install of the OS and a clean bill of
health from Disk First Aid or the disk utility of your
choice is a good way to start out any upgrade project.
These notes assume that you know how to open your case
and feel comfortable poking around the insides of your
computer. If you are a hamfisted klutz it is better to
pay someone with the expertise. Understanding that
electronic components may be static sensitive and you
have taken appropriate precautions are important.
recently had a user call who broke the plastic catch that
the heat sink spring attaches to. Let me repeat if you
are a bit ham fisted it pays to have someone with
experience do this for you. The user bought another
system.. I would have used epoxy (super glue won't work!)
to repair a break like this but again you need experience
using epoxy on delicate materials. If you aren't
comfortable doing your own repairs there are always folks
like us who are happy to help.
I was 16 I bought my first car. It as an old Ford 6
cylinder. I was tuning it up putting in new plugs and
points and a friend stopped by. He said we need to check
your pedal. I didn't know what he was talking about. He
told me to hang on to the throttle cable and got in the
car and pressed the gas pedal to the floor. The throttle
as about a 1/4" from being totally open. He helped me
optimize my carburetor. He said that most car makers
never give you all the pedal. I never did know why but
perhaps they had their reasons. From then on each new or
used car I bought got optimized. I want all the
have processors and that equates to an engine in a car.
The manufacturers have to make sure your computer runs
under a wide ranges of circumstance and that sometimes
they compromise reliability over performance. Now I don't
know about you but I don't run my computer in a 100
degree room. If I did I might have problems bumping up
the processor speed. Some of the units we sell have had
their processors optimized. We note them in the
descriptions if this is so. We test them to insure that
they are reliable at the higher speeds.
and IBM manufacturer the processors. Apple many times set
the speed levels very conservatively. We sometimes bump
those processors one notch and thoroughly test them and
check temperatures at the next higher rating. If they
aren't rock solid we don't sell them. Many very possibly
would be stable at even higher ratings. We also make sure
that your heat sink is in solid contact with the
processor and in some cases use a silver heat sink
compound to insure your unit is running as cool as
possible and many times cooler even at the higher ratings
than the stock unit was running. Some of our servers and
many of our work stations which run 24/7 for years have
done so with optimized processors.
think you deserve to have all the pedal your computer has
to offer without sacrificing reliability.
you foul up the processor you will have to replace it. If
you are not prepared to buy a replacement or upgrade do
not start. You possibly could damage your motherboard if
you don't make sure the pins are properly aligned on the
processor before applying pressure.
turn on the machine with the heat sink off of the
processor. In fact unplug the machine while you have the
heat sink off.
THERMAL GREASE GOOD OR
If you use thermal grease
a small amount is simply a very tiny amount. Keep in mind
that when the heat sink is clamped down it is going to
spread. A thin film covering the processor is all that is
required. Too much and it gets under the gasket and
shorts the capacitors. I sometimes apply a thin film on
the heat sink gasket almost wiping it back off. This
prevents the processor from welding itself to the gasket
and probably puts as much heat sink grease as anyone
needs. I like an use the silver based compounds.
It is okay to boot your
machine for a minute or two with the door open. Keep the
time down to a minimum. The processor relies on the large
interior fan to cool off the heat sink. For purposes
other than a quick test you should always have the case
You do this at
your own risk. I make no claims or warranties about
this information and working on the insides of anything
electronic may result in you messing the things up.
Please note that any modifications you make to your
Macintosh are made at your own risk.
Some of the images and chart are from the
website. Since the original was in Japanese and sparse on
info, I converted them to English.
of processor, note PLL position in
resistors on R1 and R5 making this an 867 mhz
processor. Also NOTE that the resistors are not
First things first:
Use Apple System Profiler to determine what
your present clock speed is. On the diagram
below find out how many traces are required to
set your system's speed up to the next level.
You will need a trace pen like those used to
repair automotive rear window defoggers. I use a
pen called the Circuit Writer but these are
increasingly hard to find. They don't work very
well and clog up almost instantly. I ended up
opening the pen by screwing off the tip and
using a toothpick to paint the traces.
- Remove the cooling
fan by taking out the two screws from the back of the
computer. Unplug the fan from the motherboard. Clean
the fan. If you use your wife's makeup brushes don't
let her catch you.
- Use needlenose to
remove the heatsink clips popping loose the front of
the clips first. Use a small flatbladed screwdriver to
pop loose the back of the clips. Be extremely careful
not to damage the motherboard beneath the clips. Note
orientation. The dimples that contact the heat sink
must be replaced in the same position. If you forget
simply hold the clamps over the processor. The dimple
should be centered over the copper processor center. I
bend the spring clamps (very slightly) equally on both
sides so that they put a bit more pressure on the heat
sink to insure a good contact.
- Pull the heatsink
straight up and away and set aside.
- Remove the 4 phillips
screws holding down the processor.
- Between the topand
bottom screw on the right side of the processor
underneath is a plug. I put my finger under this point
and grab the left corners of the processor board and
pull straight up.
- Turn the processor
over being careful not to bend any of the tiny
- Carefully desolder
the resistor(s). You should view the chart below and
make a strategy before beginning. For example on the
733 to make it 800 you simply desolder one resistor. A
dental pick is handy for removing the resistors once
you have melted the solder. Be careful not to apply to
much heat or sling the solder when you remove the
- Carefully paint in
your traces. I use a toothpick dipped into the
solution from the Circuit Writer Pens (Try
and search for circuit writer). Use a dental pick or
small knife to clean any excess off. Once you have
completed your traces and are ready to reinstall
simply reverse the procedure. Make certain you are
lined up and push straight down to seat the plug. Any
misalignment here and pressure will bend the pins and
make the processor unusuable and may damage the
- ONE THING I
HAVE LEARNED: the
trace needs to be fairly thick to give the proper
connection. On units that fail to work, I usually
simply add another layer of the solution to build up
the trace and double check to make sure I have cleaned
up the excess so that no contact is made
- Reinstall the screws,
- Add a dab of heatsink
grease to the black pad on the bottom of heatsink and
wipe most of it off leaving a very thin almost see
through layer. Almost better to have too little than
too much. If excess works its way under the processor
gasket it can cause failure. If part of the black
gasket is stuck to the processor, clean it off and
apply a bit more grease to the gasket to fill in the
- Replace the spring
clips in the same orientation that you removed them.
If you weren't paying attention the dimples are
positions about the processor itself.
- Replace the fan and
plug it back in. Return your wifes make up brush (I
use a little spit to clean the dirt from the brush).
Button up the case and start up your system.
system relies on the air flow of the closed case for
proper cooling. Running your computer with the case
open for more than a few minutes can cause
Your system should make
the normal startup chime and reboot. If it doesn't push
the PMU switch behind the battery (it looks like a tiny
gray doorbell button) and count to 5 slow. Try it again.
Still no luck? Take it back apart and check your traces.
Make sure you haven't jumpered to any parts unintended
and use a small point to clean off any excess material.
Make sure your trace goes from solder pad to solder pad.
If it still doesn't work, put things back the way they
were or order a processor replacment or upgrade.
If it works okay check
Apple System Profiler to see if you are running at the
I usually load up a few
Applications to see if I notice any anomolies. Run disk
first aid which uses the processor, and drives fairly
heavily. One of my techs (Scott) like to run the Graphing
Calculator in demo mode which works extremely well for
testing. If you have the old Test Memory 1.0 program run
it in repeated mode for a few hours. If you have any
freezing or other difficulties then redo the original
setup and call it a day.
If you are successful you
may wish to try the next level of speed up, but I don't
recommend it. Keep in mind rarely will you get a stable
machine at going a full 100 mhz increment. I have
optimized about 100 processors so far and all but one has
went one bump up with no problems even after lengthy
testing. The one that failed I accidently drug solder
sidewise as I was removing the resistor. Next time I have
the iron fired up I probably can get it to work as well.
I think the 450 mhz processor and the 500's are the exact
same chip but can't prove it. The 450's all run 500 as
stable as the original 500's. I think the same is true of
the dual processor 450's after having optimized a few
dozen of them now. I have only upgraded a few 466 Digital
Audio's with no problems. Recently
we bumped a few 733 mhz QuickSilver's to 800. They all
passed with flying colors. I have also bumped a few 867
mhz to 933 mhz and they have all worked fine so
G4 QUICKSILVER JUMPER
x: NO Jumper
NOTE: that the
resistors are not numerically aligned. See the image
above for the numbering sequence.
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